Improvement in fire-alarm telegraphs



2 Sheets--Sheet 1.

L. H. MGCULLOUGH. Tire-Alarm Telegraphs.

Patented Jan. 20,1874.

AM woman/100501110 caflflosa/mvzs muss) 2Sheet s-Shee t"2. H. MOGULLUUGH.

Fire-Alarm Telegraphs. No. 146,698. Patgntedlan. 20,1874.

UNITED STATES FATEN LElVIS H. ll'IOG'ULLOUGrH, OF RICHMOND, INDIANA, ASSIGNU'R OF TW'O-THIRDS HIS RIGHT TO ELLVVOOD PATTERSON AND ISAAC Gr. DOUGAN, OF SAME PLACE.

IMPROVEMENT IN FIRE-ALARM TELEGRAPHS.

Specification forming part of Letters Patent No. 146.698, dated January 20, 1874 application filed June 21, 1873.

To all whom it may concern:

Be it known that I, LEWIS H. MCOULLOUGH, of Richmond, in the county of Wayne and State of Indiana, have invented a certain Improvement in Fire-Alarm Telegraphs, of which the following is a specification:

The principal object of my invention is to lessen the liability of creating conflicting signals at the main station, resulting from turning in alarms from several boxes at the same time. To this end, I connect one pole of the battery at the main station with an earth, and use alarm-boxes, which have each a groundwire, and are so constructed that, in operating one to turn in an alarm, it cuts out all of the line beyond it, and becomes temporarily the terminal station, from which the signals are sent through the short earth-circuit. After the alarm has been sent, the short circuit is cut out, and the continuity of the line re-established automatically, so that alarms may again be sent from any box on the line.

Figure 1 is a plan View of my improved alarm-box. Fig. 2 is a horizontal section of the same. Fig. 3 is a sectional elevation. Fi et is a detail view of the spring and drivingwheel, used to move the alarm. Fig. 5 illustrates an alarm-telegraph constructed in accordance with my invention.

The same letters of reference are used in all the figures in the designation of identical parts.

The mechanism for giving an alarm is operated by a spring, A, through the medium of a train of wheels, the arbors of which have their hearings in the frame B, the speed of the train being regulated by an escapement-wheel, (J, and regulator D. The latter carries an adjustable ball, cl, which is shifted in or out, according as the train is to run faster or slower. The spring is wound up by a sliding rack, E, which gears into a pinion on the arbor of the drivingwheel of the train, and is carried back to its normal position as the work runs down. The stem E of the sliding rack protrudes through the end of the frame, and terminates in a knob, of rubber or other non-conducting material. To set the wheel -work going, the rack is pushed forward until the knob E brings up against the frame or box. The return movement of the rack is limited by a stop-pin, c, in its other end coming in contact with the frame, and the extent of its movement is such that the arbor f of the wheel-work will receive exactly three revolutions every time the wheelwork runs down after having been wound up. The main line enters the alarm-box at the screwcup a, to which one end of the line-wire is secured, and which is in metallic connection with the arbor f. The other end of the linewire is secured to the insulated screw-cup b, from which a short end of wire, 0, is carried, and connected to an insulated platinum disk,

0 secured to the end of the frame or box, in

pierced by close proximity to the stem E of the sliding rack E, upon the inside of the box. The rack is provided with a short wire spring, 0 (see Fig. 2,) which, when the wheel-work run down and the rack consequently in the position shown in Figs. 1 and 2, bears with its end against the platinum disk 0 and thus establishes a metallic connection between the two ends of the line-wire. The arbor f carries at one end a circuit-disk, F, the peripheral surface of which is bound with a band of rubber or other suitable non-conducting material, platinum pins or spurs f, which are secured to the metallic portion of the circuit-disk. The number of the platinum pins and their arrangement on the disk are such that at each revolution of the disk they will close the circuit such a number of times and at such intervals as to indicate the number of their box at the main station. The alarm illustrated is supposed to belong to a box numbered twenty-one. Hence the circuit-disk is provided with three platinum pins, the space between the second and third one being somewhat greater than that between the first and second, and the space between the third and first being still greater. An idler disk, Gr, bound with a platinum band, 9, is pressed constantly against the periphery of the circuit-disk by means of a spring, 71, the fast end of which is secured to the insulated screw-cup t. The idler G is insulated and carried on a stud of the pivoted arm H, which is also acted upon by a spring, h to keep it bearing toward the circuit-disk. From the insulated serew-cupvl a wire, it, is run to earth. When the alarm is at rest the first platinum spur on the circuitdisk will be just a little in advance of the point of contact between the disks F and G, and the wire 76 consequently out of circuit, as the insulated disk G, with which alone it is in metallic connection, bears against the non-conducting surface of the circuit-disk F. As long as all the alarms are at rest an uninterrupted current flows through the main line, but the moment any one of the alarms is being wound up by pushing in the rack E the main circuit is broken, and as the wheel-work runs down momentary short circuits are established through the platinum spurs of the circuitdisk F, and the intermediate connections between it and the screw-cup i, by means of the ground-wire is sounding the alarm in the usual manner at the main station. The disk F making three revolutions the alarm will be sounded three times in succession.

I prefer to make the connecting-wire c 011 the rack E in the form of a bent spring, the

' end of which shall touch the platinum plate 0 just previous to the stoppage of the wheelwork, to insure the unfailing contact of such wire-spring and platinum plate. The main shaft turns the driving-wheel as the mainspring 1111 coils through the medium of a ratchetwheel and pawl in the ordinary manner, the driving-wheel being loose on the shaft. The alarm, in case the mainspring be broken, can still be set ageing by the operator, who will then first push the rack forward as heretofore, and subsequently pull it back slowly to the end of its stroke. In Fig. 5 I have indicated the manner of laying a line of my improved fire-alarm telegraph. The line-wire K, starting from one pole of the battery L, the other pole of which goes to earth at Z, is connected to theseveral alarms, M, in the manner heretofore explained, and may go from the last alarm of the line to earth at Z, or it may terminate at said box without going to earth, in which case the circuit is completed through the earthwire 7:, when the box is put in operation. Each alarm is also connected, by a short wire, is, to

an earth, a. When an alarm is being turned in from N 0.3, all of the line beyond is cut out, and remains cut out until the end of the alarm, when the circuit is automatically re-establishcd through the entire line. The signals are sent through the ground-wire of the active alarm, which temporarily becomes the terminal station of the line.

It is evident that the spring h may bear directly against the circuit-disk, and the disk G be dispensed with, but I prefer to use it for the sake of reducing friction. The ratchetwheel on the main-shaft is. so spaced that it can act upon the driving-wheel only in such a way as to impart to the circuitdisk entire revolutions, either one, two, or three.

\Vhat I claim as my invention, and desire to secure by Letters Patent, is

1. In a fire-alarm telegraph the combination of an earth for each signal-hon with an earth of the battery at the main station, substantially as and for the purposes set forth.

2. In a fire-alarm telegraph the combination of the main-line alarms, which when brought into action break the continuity of the main line, an earth for every alarm-box, and an earth of the battery at the main station, substantially as specified.

3. The line-wire metallically connectedwith one end to the alarm, and with the other end to an insulated metallic plate, 0 in combination with the circuit-breaker c on the sliding rack E, which winds up the motor groundwire is, and a mechanism for closing and breaking the connection between the line-wire and the ground-wire.

- 4. The combination of the line-wire connected to the alarm, as described, the sliding winding-rack E, carrying the circuit-breaker c circuit-disk Ff, ground-wire k, and spring 11, with or without the insulated disk Gr, sub stant-ially as set forth.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

L. H. MoCULLOUGI-I.

XVitnesses:

B. Enw. J. EILS, VVILMER BRADFORD. 

